Thread rolling device having adjustably matched die rolls



June 1, 1954 E. r. SCOTT 2,679,773

THREAD ROLLING DEVICE HAVING ADJUSTABLY MATCI-IED DIE ROLLS Filed May 8. 1952 IN VEN TOR.

Elng er'T SCOPE CK- f- ATTORNEY Patented June 1, 1954 UNI S Mass.,1a= corporation plication M y 195 Serial-No: 286324 3 Claims. 1

This invention relates-"to 'an improvementin a thread rolling device of the type 'shown my prior application, SeriaFNo. 236 i541 filed J-uly 13, 1951.

A thread rolling device of this typecomprises a plurality of rotatively'interconnected d-ie'rolls which are freely-rotated by a 'positively" rotated work piece, and pressure of-the= dies againstthe Work serves to forcethe *dies into the work piece and graduallyform-the threa-dsthereon. The dies are mounted for a relative rotative adjustment so that they may be brought-intoan-exact matching engagement with -a thread and be thereafter held in-a'matchedsynchronism. The die rolls are rotatively-connected by means of two special gears, butfor'thepurposeof matching the threads these gearsmay be freely moved relative to each other to'permit rotating the two die rolls separately into a-proper' threadmatching relation. Thereafter, the two gears are-held in an immovable relationship so *thatthedie rolls are forced to roll together.

In my prior construction, one'of these gears is made integral with -a spindle and-the other gear is rotatively mounted on the same spindle and adapted "to be moved axially 'an'dclamped laterally againstthe first gear sothat they will rotate together after have been 'brought'into the required matching relationship. To'eifect that matching operation, the spindle is 'held-'by a set screw and thefreely rotatable=gear; mounted on an extension hub of thespindle, is freedfrom rotative contact with thespindle' gear '-byloosening a clamp nut. After 'this 'the 'tworoll dies and their associated gearsmay be turned-relative to each other until the required matching -is*-effected after which the clamp'nutis'movedforward to clamp thetwo 'gears together. "If, however, the operator of the device should forget to loosen the set screw which holds the spindle, then the first attempt at rolling 'thethread will either strip the face fthe work"oririiureitor break or otherwise damage the threads-"ofthe roll dies. Moreover, the *rotative effort required to loosen the clamping'nut which holds'the' gears together is likely to twist the spindle relative to the set screw and thus by'a' camming action set the screw against "the spindleend-makedt difiicult to remove it'and 'poss'ibiy'injure the screw head.

One object ofthis invention '"is '-:to .provide a construction which will "prevent "that "type :of accident and will insurethatnitherroll nor its associated gear can be "heldilocked 'Tduring Luse. To this end, I provide a'set of wrenches, "one "of which is insertedWithinahble in the other which are so arranged thatthe operative 'ends of the f two'wrenches araaxially' aligned. One "of these *ends =is=arrangedto=engage '-a* part associated with the spindle while the other wrench-engages the clamping nut whichmormally serves to hold the -two gearstogether. Thus the two parts may be relatively rotated to loosenthe gearsor to c'lamp them together.

As a further -feature of the invention, if the --wrenchengaging s-urfaces were external, an improper use-of an incorrect size'of"adjustable wrench would cause the =sq-uared-or flat surfaces of the external wrenchflttingpartto "be injured or rounded and later make'it diliicult toadjust the *rolls. -A=lso, any such a projection arranged I to fit a wrench may extend intothe work zone and interfere at times with the use of the thread rolling device.

Hence, --a further object of the invention is to: have all wrenchlitting parts arranged as internal -suflaces and without any "projecting portions-which could be iniured or cause inconvenience in-the'useof the "machine'or'injure the -"operator.

Another object is to provide a -set of tools which will 'removably -'serve' for freeing the roll driving-gears formatching the threads. Other objects will be a'pparentin the "following disclosure.

"Referring to the drawings 'which illustrate this invention as applied to a device "of the type shown my prior application:

*Fig. 1 is a-'vertical elevation oftheroll' device which is "partly 'loroken away to *show the gear connections betweerrthe "diero'lls and the positional -adjustments of-the rolls FigAZ -is a sectional viewtaken on the-line .2-- 2 ofFigJ 1;

Fig.3 is a sectional'view-taken on the line"33 of Fig. l 1, which is broken away to show details;

-Fig. i is an enlarged fragmentary sectional =view showing the two -interfitte'd axially aligned wrenches in their "operative arrangement "for -loosening the-two interconnecting'gears to permit matching of t the" die *rblls and Fig. 5' 'isa fragmentary" view'similar "to ;Fig. 14 showing-a modification.

"The "preferred embodiment :of .my invention, asil-lustrated, comprisesitwo'die rolls l0 and l I which are 'respectively 'rotatably "mounted on parallelaxles carrie'don a suitable support,- such asthe yoke shaped body 1L The die rolls may havethreadsforme'd helically 'on their surfaces in -accordance "withstandard' practice, and they are arranged to be thrust directly against the periphery of a positively rotated work piece W and moved laterally thereof until the work piece is substantially diametrically positioned on a line connecting the axes of the die rolls at which time the threads are completed.

In order to provide for adjustability of the die roll positions to accommodate different sizes of work and suitably sized die rolls, each roll axle I3 is pivotally mounted on adjustably movable members, shown as two pairs of swinging arms I4 and I5. The two pivoted arms I4 support one end (the left in Fig. 2) of each die roll axle, and the pivoted arms I5 carry the other end of each axle. The arms [4 and the arms I5 are respectively symmetrical but mounted in a reverse arrangement, so as to hold the roll pins at their outer ends. Each swinging arm has a substantially cylindrical or disk-shaped portion I1 and a laterally projecting die roll supporting projection I8. The cylindrical periphery of the diskshaped part I! rotatively bears on a recessed cylindrical bearing I9 formed in the supporting yoke body I2. The right hand arm I5 has a furtheir bearing provided by the T-shaped pivot post 20 which is threaded at its inner end into a hole in the yoke I2. The post has a cylindrical hearing surface 2| pivotally supporting an inner cylindrical surface 22 Within the disk I! of the swinging arm I5. An enlarged or T-head 23 fixed to the post 20 is mounted in a cylindrical recess within the disk I], and it is provided with spanner wrench holes 24 so arranged that the threaded end may be turned into position in the yoke shaped mount I2. These parts are so made that the external cylindrical surface 2| and the internal bearing surface I9 in the yoke I2 both cooperate to support the cylindrical disk l! for a very accurate rocking movement. The other arm I4 has a similar central post 25 which is longer than the post 20 to provide for a gear assembly, as will be described. This post likewise has a threaded end 25 and the T-shaped cylindrical bearing head 2'1 riding in a cylindrical depression within the rocking arm l4 and helping to support the arm.

The position of each of the die rolls relative to the work piece W is adjusted by means of an adjustment push screw 30 and a set screw 3| engaging each rocking arm I4 and I5. Each screw 30 passes through the projecting yoke arm of the support I2 and engages the substantially flat face 32 of the adjacent roll supporting swinging arm portion |8. Each set screw 3| is located in a threaded hole near the base of the U-shaped body I2 and arranged to engage a wide angled slot 34 formed in the periphery of the disk IT. The screws 30, 3! and the slots 34 are so arranged that the inner curved end of each set screw may rockingly bear on the adjacent fiat wall faces 32 and 34 and cause rocking of the disk I! and move the associated swinging arm and its end of the die roll towards or from the Work axis. Thus, by adjustment of the two screws the two opposite supporting arms I4 and I5 may be manually adjusted inwardly, or outwardly, to the required extent after each set screw 3| has been backed off, and then the latter may be set into position to hold the swinging roll support in a fixed and adjusted position. It will be appreciated that the position of the die roll may thus be very accurately adjusted by careful manipulation of the adjusting screws.

In this construction, it is required that the two die rolls be rotatively connected to rotate in synchronism. For that purpose, the die rolls are preferably connected by a gear train which provides for a matching of the threads of the die rolls relative to the work. The right hand arm [4 of Fig. 1 is therefore shaped to provide space and a bearing mount for a gear which is secured to the die roll II by a key 4| locking between two driving lugs on the near side of the die roll. That gear 40 and the die roll are freely rotatable on the bearing shaft I3 which passes axially through the roll and is fitted within the two opposed rocking arms I4 and I5. The gear 4!} meshes with a further gear 44 mounted for free rotation on a cylindrical bearing extension or boss 45 projecting inwardly from the rocking arm M. The cylindrical bearing portion of the post 25, which helps to support the rocking arm I4, is long enough to pass through that boss and form the pivot for the arm I4. Similarly, the opposed die roll ID has a gear 41 (left hand portion of Fig. 1) freely rotatable on its shaft I3 and secured to the die roll by a driving key. That gear 41 meshes with a large gear 48 likewise pivotally mounted on its associated bearing surface on the boss 45 of the swinging arm I4.

Between the two gears 48 and 44 is a gear assembly that connects the die rolls rotatively and yet permits matching adjustment. This comprises two gears 50 and 5| (Fig. 3) which are adapted to be rotated adjustably relative to each other. The gear 50 is integral with a central rotatable shaft 52 which is rotatably mounted in a suitable bearing between the yoke arms of the body I2. This gear meshes with the gear 44 of the right hand die roll I I of Fig. 1. The other gear 5| meshes with the gear 48 of the left hand driving roll I0, it being noted that these gears 44 and 48 are cut away and inverted in position so that they contact only with their associated gears, as illustrated. The gear 5| is freely mounted on a cylindrical bearing extension 54 of the spindle 52. The spindle is threaded at its end 55 for engagement with a nut 55. The top face 53 of the gear 50 (Fig. 3) is flat and may be forced against a correspondingly parallel face on the freely rotatable gear 5| by tightening up on the nut 56. This brings the two gears into a tight frictional engagement so that after an adjustment has been made, they will rotate together.

In accordance with this invention, as shown in Figs. 1 to 4, I provide the end of the spindle 52 with an internal wrench socket $0 and the nut 56 with another internal wrench socket 52. These are preferably hexagonal in shape and made suitably. A wrench key applied to the socket 60 will serve to hold stationary the spindle 52 and its gear while a second wrench applied to the internal surface 62 of the nut 56 will serve to turn the nut 55 relative to the spindle 52 and thus either loosen or tighten the connection between the two parallel friction surfaces of the shoulder 53 and the inner end face of the gear 5|. It will be observed that the internal nuts 60 and 62 are located inside of the plane defining the outer face 63 (Fig. 3) of the device. Hence the various gears with the associated spindle are concealed and there is nothing projecting which can in any way interfere with the treatment of the work or the operation of the device.

I have provided a special set of wrenches 64 and 65 adapted to fit into the two sockets 60 and 62 (Fig. 4). One wrench has a hollow shank into which the other wrench interfits axially so that both may be applied to .their respective sockets the internal 'hexa'gonalisocke't .vrecess 60 of the extension 254 of the spindle S52. shaped wrench 4564: has ran extension 68 at right .:angles to vthe:hand-le portion which also has a hexagonal akey at'its:endthatLfits:rproperly within the hexagonal SOCKEULGZ 'Of the nuti56. To provide for: this coaxial rassembly of athe two wrenches, the portion 68 .ofxthe wrenchi64 is made'consider- .ably largerrimdiameter thantthe :part 66 of the otherwrench,.andiit. isapronideduwith 2a: cylindrical hole :69 co.-'axia'l :its nsocket -"fitting key portion ;and; so rshapedrthatwrthe part i166 :of :the

wrench 65 may be slid into and freely turned within this hole. Thus the wrench 65, 66 manipulates or holds theinternal hexagonalsurface 60 of the spi-ndle -v521while thezxhexagonal portion 68 of the wrench B4 operatively, engages the internal surface of the nut 56.

By: applying these two wrenches to the two. internal sockets "as described, -the spindle 52 may be held stationary by means of .the wrench 65, 66 while the other wrench64, 68 serves to turn the'nut 56 and loosen the-frictional engagement between the gear 5| and the shoulder- 53 of the spindles52. This frees the-two-gears=5| and 50 and permits the die rollstobe-manually-rotated relatively to provide a proper matching with a thread gauge or a finished work piece. Then by a reverse manipulation of the two wrenches the spindle 52 is again held stationary while the nut 56 is tightened to thrust the gear 5| against the shoulder 53 of the spindle 52 and thus make the two parts rotate in unison. Thus the helical threads of the two die rolls may be brought into a very accurate matching engagement with that gauge by merely rotating one roll relative to the other as permitted by the slippage of the gear 5| relative to the gear 50. Thereafter the nut 56 is tightened to clamp the two gears 50 and 5| together so that they rotate as a unit. Since the two die rolls are correspondingly connected together by the adjusted gear train, they must rotate in synchronism and in the desired matched relationship as provided by slipping the gears 50 and 5|. Since the gears 4'4 and 48 are axially mounted on the pivot of the swinging arm l8, the die roll gears 40 and 41 are always running on the same pitch line of the larger gears 44 and 48 as the arms l8 swing. Thus any swinging adjustment of the arms I 8 cannot affect the gearing center line distances but does change the thread matching relationship.

An adapter may be used for mounting the die rolls on a lathe or other machine tool, which is arranged to provide both swinging and axial movement of the die rolls. The yoke body I2 may have a projecting lug or shank 10 pivotally mounted on a pin 1| carried by the yoke arms 12 of the adapter shank 13 which is suitably mounted on the machine tool. This provides for a lateral displacement or swinging of the assembled die rolls relative to a piece of work which is not correctly located axially between the two rolls. Also, a slight clearance is left between the inner faces of the yoke arms 12 of the supporting shank of the adapter and the outer parallel flat sides of the lug 10 of the yoke body l2 so that the yoke body may move endwise on the pivot pin 1|. Two coiled springs 15 are mounted in sockets 16 in the outer faces of the shank 16, and they bear against the inner faces of the adapter yoke armsi=12 and thus tendutoz-holdi' the "die ro'll: supporting ibodyi.|.2 located centrally within: the yoke .13. Thisxaxialsmovementxthus provided by the springs i- 'l5'will ease rany ilateral .thrust on .the

flanks of the 'thI 8adSu0fithB. dievrollsiandi tend to returnrthe :yokeubo'dy ".12 :to a. central:- :position when that :pressure has been :released. This provides 'analmost universaLmount for :the .die

rolls. .-A..set screwv oratpin I2 .111 .WillThOldi the :pivot shaft 1| fixed inztheiyoke:12isozthatltheradie roll body I2 may swing without any movementtzof the .supportingtshaft.

It will now be appreciatedwthat this :construction provides :for: full EfiJUStabiIL LtyflOf :the "rolls toward :andfromvthe work-.-within=:-. the :capacity 5 of thedevicezand iaccordingzto the sizeiofthe: rolls, and this addustmentavill:notzzaffectthe:operation pins or axles I-3:are:sepanatelymovable,ieach:may be independently. 1adjusted.:by manipulationiofits screwst3|l and 3|. Thisaprovidesifor-radiusting or tilting the two; rollrzpi-ns; accuratelyzand .locking them inaxialgpara'llelism with the work, so as to correct for taper within .the :pin :and1;bearing tolerances. Also, theqyielding mountc'providedby the slight. clearancehetween zthe shank: 1-3 andithe yoke arms 12 and the centering springs l5 (Fig. 2) serves to relieve the side thrust on the die roll threads as work penetration progresses and the apparent work diameter decreases. The pivot pin 1| permits the rolls to float into full contact with the work and compensate for any out of alignment of the work and die rolls. The rolls are usually left freely rotatable, except as they are geared together, and their rotation is effected solely by the rotation of the work piece therebetween.

As an equivalent construction, the key and the socket for either or both wrenches and the associated gear or clamp nut may be interchanged. For example, as shown in Fig. 5, the clamping nut 56 has a reduced end portion '88 which provides an annular recess between it and the front arm I 4 into which the hollow end 82 of a wrench 83 may be inserted. An external surface of the end portion 88 is made hexagonal or of other suitable shape which is adapted to fit a corresponding shape on the internal surface 84 of the wrench 83, so that by means of this wrench the nut 56 may be turned on the threads on the spindle 52 for loosening the gear 5| from frictional engagement with the shoulder 53 on the spindle.

Similarly, the spindle 52 is provided with a reduced end portion 86, the external surface of which is made hexagonal or of other suitable shape for fitting within the socket 81 of corresponding shape which is provided in the end 88 of the second wrench. These two wrench parts 83 and 88 are axially interfitted the same as shown in Fig. 4. In this construction, the internal surface 84 of the wrench 83 is continued as an open ing, preferably cylindrical in shape, into which the second wrench 88 fits loosely and within which it may be turned freely. Other arrangements of these parts will be readily suggested by Figs. 4 and 5. That is, either part may be provided with an external key surface, while the other is correspondingly recessed to fit the same. It will also be noted that in the Fig. 5 construction, all of the parts are held within the boundary 7 surface 63 of the yoke body. If desired, the interfitting facesat 53 between the gear 51 and the spindle 52 may be milled to provide very fine teeth or corrugations which prevent slippage, or they may be otherwise made for the purpose.

Various other modifications may be made in this construction by one skilled in the art, and it will be understood that the above description of preferred embodiments is not to be interpreted as imposing limitations on the appended claims.

I claim:

1. A thread rolling device comprising rotatable die rolls having work rolling threads thereon, a support, bearing axles on the support carrying the rolls in axial parallelism, a gear train connected between and synchronizing the rotation of the rolls which includes two axially aligned, relatively rotatable gears having contiguous parallel frictional side faces, each of which is respectively connected to rotate with one of the die rolls, mounts for said gears whereby one gear is axially immovable and the other gear is axially movable for releasably engaging the friction faces in a roll driving relationship, a clamp nut for moving the axially movable gear and a threaded part carrying the nut which is associated with the immovable gear, said nut and immovable gear having concentric wrench engaging faces so arranged that they may be simultaneously engaged by separate wrenches for releasing the clamp nut to provide for relatively rotating the die rolls and adjusting their matching relationship.

2. A thread rolling device according to claim 1 comprising a spindle provided with a threaded end which is integral with and projecting axially from the axially immovable gear, said axially movable gear being rotatively and slidably mounted on the spindle, and the clamp nut being threaded on said threaded end.

3. A thread rolling device according to claim 1 in which said support has an outer face and the clamp nut, the gears and their wrench interfitting parts lie wholly inside of the said surface, so that when the wrenches have been removed there are no projecting portions of the adjustment parts.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,496,116 Browne June 3, 1924 2,599,489 Schmidt June 3, 1952 FOREIGN PATENTS Number Country Date 317,421 Italy May 8, 1934 549,838 Germany May 2, 1932 580,949 Great Britain Sept. 25, 1946 

